Inductor form



Jme 11, 1957 J. A. STROBLE INDUCTOR FORII Filed Oct. 31. 1952 INVENTOR JOE A. STROBLE ATTORNEYS United States Patent INDUCTOR FORM Joe A. Stroble, La Mesa, Califi, assignor to the United States of America as represented by the Secretary of the Navy Application October 31, 1952, Serial No. 318,143 7 Claims. (Cl. 336-192) (Granted under Title 35, U. S. Code (1952), sec. 266) The invention described herein may be manufactured and used by or for the Government of the United States of America for governmental purposes without the pay ment of any royalties thereon or therefor.

This invention relates to inductors and more specifically to a new and improved inductor form.

In the fabrication of inductor forms previously used the forms have been of such construction that the use of metal fasteners was necessitated when the form was other than tubular in shape. Heat developed in these metal fasteners and lowered the Q of the coil positioned on the form. Also presence of these metal fasteners gave poor dielectric characteristics to the inductor form and often resulted in arcing and unexpected breakdown. These prior forms were also generally of great weight and bulk and would not withstand high degrees of shock, vibration and heating.

It is accordingly an important object to eliminate metal, other than necessary electrical connectors or terminals, in the fabrication of an inductor form.

Still a further object is to provide an inductor form fabricated from identical parts which are preformed to interlock on assembly without the use of metal connections.

Another object is to provide an inductor form fabricated of preformed interlocking parts which hold assembled position upon the securing of a preformed inductor coil thereon.

It is a further important object of this invention to provide an inductor form capable of withstanding high degrees of shock and vibration.

It is still a further important object to provide an inductor form capable of withstanding large electrical loads without causing excessive heating and burning of the form.

A still further object is to provide an inductor form constructed of material of great strength, light weight, and capable of withstanding excessive heat while also being capable of Working by grinding and drilling.

Other objects and many of the attendant advantages of this invention will be readily appreciated as the same becomes better understood by reference to the following detailed description when considered in connection with the accompanying drawings wherein:

Fig. l is a view in perspective of an embodiment of the invention;

Fig. 2 is a further view in perspective of the embodiment of the invention shown in Fig. 1 wherein supports are provided for the coil form assembly;

Fig. 3 is a view in cross-section taken at line liliil on Fig. 2;

Fig. 4 is an end view of the embodiment shown in Fig. 2; and

Fig. 5 is a view in perspective of one of the interlocking coil holding plates of the embodiment illustrated in Fig. 1.

One embodiment of the present invention is illustrated ice in the drawings, in which 10 designates an inductor coil which is preformed and secured onto an inductor form. This form comprises four identical interlocking coil holding plates 11, of material of low dielectric constant, such as silicone glass fiber.

Each of the plates 11 has a series of notches 12 formed in one longitudinal edge and spaced along the length thereof in accordance with the desired spacing between the turns of the coil 10. Each plate on the edge opposite to the notched edge has projections or tongues 13 which are received into openings or slots 14 formed near the notched edge of the adjacent plate. Spaced openings 18 are provided in the plates for venting the form and improving the dielectric characteristics. The notched edge of each plate 11 extends outwardly beyond and overhangs the abutting edge of the adjacent plate, as shown in Figs. l3.

it will thus be seen that with this construction the four plates 11 are maintained in assembled position upon the securing of the preformed coil 10 thereon. The coil may be positioned on this assembly by screwing it from one end of the assembly toward the other end thereof, the notches 12 serving to guide the turns of the coil.

The ends of the coil 10 are secured as by silver plated brass screws 15 through special holes 16 formed in one or more of the plates 11, depending on the location of the coil thereon.

Each plate 11 at both ends thereof has secured thereto a spade lug 20 as by silver plated brass rivets 21. As

shown in Fig. 2 the spade lugs 20 extend through any 'four of eight openings 22 provided therefor in end supports 23 and 24 and are utilized to secure the body of the form, comprised of the four plates 11, to these end supports as by self-locking nuts 25. The selection of a particular four of the eight holes permits rotative adjustment of the form body to provide for an optimum location of a tap line 31 on the coil, as shown for instance in Fig. 2. At its opposite end the tap line 31 is passed through an aperture in end support 23 or 24 and is connected to the spade lug with which it is aligned. The spade lug thus forms the tap-off connecting post. Obviously, a greater number of adjustment openings 22 might be provided, if desired, for finer adjustment of the body of the form in regard to the optimum location of a tap on the coil.

Mounting brackets 26, 27, formed of any suitable strong and light weight material, and tubing bracing 28 give added stifiness to the assembly shown in Fig. 2. Brackets 26, 27 are formed arcuatcly as at 29 to follow the curvature of the coil, in order to provide desirable dielectric characteristics.

Obviously many modifications and variations of the present invention are possible in the light of the above teachings. It is therefore to be understood that Within the scope of the appended claims the invention may be practiced otherwise than as specifically described.

What is claimed is:

1. An inductor comprising a preformed coil, four elongated thin plates of low dielectric constant material mounted together so as to enclose an elongated space which is square in cross section, each said plate having an edge surface in abutment with a face surface of one of the other plates, said face surface of each of the plates extending beyond said edge in abutment therewith, the edge opposite to said abutting edge on each of said plates having a series of spaced notches to receive the convolutions of said coil as the coil is threaded onto said mounted plates, each said first mentioned edge having ears and each said face surface in abutment therewith having apertures to receive said ears.

2. An inductor form comprising a preformed coil, four elongated thin plates of low dielectric constant material mounted together so as to enclose an elongated space which is square in cross section, each said plate having an edge surfacein abutment with a face surface of one of the other plates, saidfacesurfa'ce of each of'the plates extending beyond said edge in abutmentthere'with', the edge opposite tosa'id' abutting edge'o'n-ea'ch of 'said plates having a series of spacednotches to receive'theconvolutions of said coil as the coil is threaded upon the assembled'plates, each said first mentionededge having ears and each said face surface in abutment therewith having" apertures to receive said ears, a" pair of threaded spade lugs secured respectively; to the eiid portions of each of said plates and extendedtherefrom, a pair of end plates of low dielectric constant material and secured in abutment with the end edges of said-first named plates by said spade lugs.

3. An'inductor form comprising a preformed coil, four elongated thin" plates of silicone glass fiber material mounted together so' as to enclose an elongated space which is square in cross section, each'said plate having an edge surface in abutment with a face surface of' one of the other plates, said face surface of each'of the plates extending beyond said edge in abutment therewith, the edge opposite to said abutting edge on each of said plates having a series of spaced notches to receive the convolutions of said coil as the coil is threaded upon the assembled plates, each said first mentioned edge having ears and each said face surface in abutment therewith having apertures to receive said cars, a pair of threaded spade lugs secured respectively to the end portions of each of said plates and extended therefrom, a-pair of end plates of silicone glass fiber material and secured in abutment with the end edges of said first named plates by said spade lugs, apair of mounting brackets secured respectively'to said end plates, and supporting spacer bars secured to said brackets.

4. An inductor form comprising a preformed coil, four elongated thin plates of silicone glass fiber material mounted together so as to enclose an elongated space which is square in cross section, each said plate having an edge surface in abutment with a face surface of one of the other plates, said-face-surface of each of the plates extending beyond said edge in abutmentther'ewith, the edge opposite to said abutting edge on each of said plates having a series of spacednotches to receive the convolutions of said coil as the coil isthreaded upon the-assembled plates, each said first mentioned edge having ears and each said face surface in abutment therewith having apertures to receive said ears, apair of threaded spade lugs secured respectively to the end portions of each of said plates and extended therefrom, a pair of end plates of silicone glass fiber material and secured in abutment with the end edges of said first named plates by said spade lugs, each said end plate having eight holes so spaced thereon to receive any four of said spade lugs whereby the coil and assembled longitudinal plates therein may be rotated to an optimum position for tappingthe coil, a pair of mounting brackets secured respectively to said end plates, andsupporting spacer bars secured to said brackets.

5. An inductor form for a preformed coil c'omprisiriga preformed coil, a plurality of plates of material of low dielectric constant, each of said plates having a plurality of ears along one edge thereof and a plurality of apertures formed therein near the opposite edge thereof, a plurality of notches formed in said opposite edge of each of said plates for receiving.theconvolutions of said coil, said plates being interlocked together wherein said ears of each of said plates are in interlocking relation with said apertures in an adjoining plate, to thereby form a closed loop'ofp'lates, said 'coil beingthreaded onto-said loop of plates thereby to maintain the plates interlocked together.

6. An inductor comprising a pluralityof plates of material of low dielectric constant, each of said plates having a plurality of ears along one edge thereof and a plurality of apertures formed therein near'the opposite edge thereof, a plurality of notches formed in said opposite edge of each of said plates, said plates being. interlocked togetherwherein saidears ofeach of said plates are in interlocking relation with said apertures in an adjoining plate, to thereby forma closed loop of'plates, and an electrically conductive coil surrounding the assembly of said plates, s'aid coil'havingit'stu'rns seated in said'not'ches thereby to maintain said plates in said closed loop.-

7. An inductor comprising'la'multisided elongated'form of closed-loop cross section and having the sides interlocked at the'corners ofth'e'loop, each of said sides having one of its-edges terminated at one of said corners of the loop and having its opposite edge extended beyond another of said corners, each said opposite edge having spaced notches therealong,a preformed coilthre'aded onto said form andhaving the convolutions thereof received respectively into" said notches, said coil retaining the form insaid closed-loop cross section, a support for the said form and coil thereon, said support including a pair of spaced parallel plates each having a plurality of apertures, each of said sides having a lug fastened thereto at each end thereof'and extended through one of said plate apertures, terminal means interconnecting one end of said coil and one of said lugs at one of said plates; and a fixed-position tap line interconnecting one of said lugs at the other of said plates and one of said convolutionsof said coil,- said form and coil thereon being rotatably adjustable for selected support insaid plate apertures to provide optimum adjustment of the rotational positionof said tap line on the coil.

References Cited'in the file of this patent UNITED STATES PATENTS 1,208,393 Smart Dec. 12, 1916' 1,471,340 Knight- Oct. 23', 1923 1,817,307 Hasse Aug. 4, 1931 1,895,776 Stolp a Jan. 31, 1933 2,200,059 Coyne .i May 7, 1940 2,425,304 Combs Aug. 12, 1947 2,559,988 Noyes July 10, 1951 FOREIGN PATENTS 594,102 Great Britain Nov. 3, 1947 967,947 France Nov. 15, 1 950 

